In a steam reforming reactor, under high temperatures (e.g., 400-800° C.) and in the presence of a catalyst (e.g., nickel), steam may react with a feed gas (e.g., methane) to generate a reformate (e.g., hydrogen) which may be used as fuel in a hydrogen fuel cell, for example. Because the reaction is endothermic, a heat source is needed to maintain a temperature range at which the reaction can occur. Further, as methane is converted, the partial pressure of methane decreases as the gases travel through the reactor. As such, a higher temperature is needed for the reaction to occur farther from an inlet of the reactor than for the reaction to occur closer to an inlet of the reactor.
Thus, a heater may be coupled to a portion of an outer wall of a reactor in order to heat the reactor to temperatures necessary for methane conversion along a length of the reactor. Due to low convective transport coefficients within the reactor, heat is transferred mainly via radiation. The reforming reaction immediately uses this energy in the vicinity of the outer wall, such that less energy is available to heat the inside of the reactor at locations farther from the outer wall. This may result in a low temperature zone spaced from the outer wall of the reactor. Since a higher temperature is needed for conversion in portions of the reactor closer to the outlet of the reactor due to the low partial pressure of methane in these portions of the reactor, the low temperature zone may result in elevated methane slip (e.g., un-reacted methane leaving the reactor), thereby decreasing the efficiency of the reactor.